I have a outdoor structure that I'm replacing the entire roof on but it's 20' in the air. And when I say "the entire roof" I mean everything from the trusses to roof metal. Because of the structure design I built the roof on the ground with the intent of hoisting the old roof off and hoisting the new one on but my fairly simple plan has been overcome by design changes ("sure hon, I can make that look like you want.") So now I think my only option is to place two beams under the frame, attach my hoist cables to the ends of the beam and hoist away. I'm hoping someone can tell me the least expensive thing to use as my lift-beams.

The structure base is 10'x10' made from 4-4x6 treated yellow pine. The total weight of this roof is about 2700 pounds. My rafters extend about 2' below the base and 3' beyond so the outer dimensions are 16' x 16'. My thinking is to use two engineered wood beams/pipes/square tubing/dimensional lumber (this is where I need your help) to place parallel under the structure, use 4x6 scraps as spacers under the base to keep the YTBD beam off my rafter tails and attach my straps to the ends and hoist away. I can add spacers above if I need to but I don't know what to use under the roof structure to lift it. I also have to be able to be able to manhandle the YTBD 20' long "beam" once the roof is in place since I can't just drop it to the ground, though I can take it apart if I need to.

I've looked at the engineer calculators and figured all the loads but that just gives me a bunch of numbers that don't tell me what to use so I'm hoping someone on here can give me that answer. Bubba up the street has provided his input but I think I'll ask an engineer. I can upload pics if it'll help. Small Bio